Bluetooth: Save connection interval parameters in hci_conn

This patch creates two new fields in struct hci_conn to save the
minimum and maximum connection interval values used to establish
the connection this object represents.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Stop scanning on connection

Some LE controllers don't support scanning and creating a connection
at the same time. So, for those controllers, we should stop scanning
in order to establish the connection.

Since we may prematurely stop the discovery procedure in favor of
the connection establishment, we should also cancel hdev->le_scan_
disable delayed work and set the discovery state to DISCOVERY_STOPPED.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Introduce connection parameters list

This patch adds to hdev the connection parameters list (hdev->
conn_params). The elements from this list (struct hci_conn_params)
contains the connection parameters (for now, minimum and maximum
connection interval) that should be used for establishing
connection.

The struct hci_conn_params also defines the 'auto_connect' field
which will be used to implement the auto connection mechanism.

Moreover, this patch adds helper functions to manipulate hdev->conn_
params list. Some of these functions are also declared in hci_core.h
since they will be used outside hci_core.c in upcoming patches.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Make find_conn_param() helper non-local

This patch makes the find_conn_param() helper non-local by adding the
hci_ prefix and declaring it in hci_core.h. This helper will be used
in hci_conn.c to get the connection parameters when establishing
connections.

Since hci_find_conn_param() returns a reference to the hci_conn_param
object, it was added a refcount to hci_conn_param to control its
lifetime. This way, we avoid bugs such as use-after-free.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Use connection parameters if any

This patch changes hci_connect_le() so it uses the connection
parameters specified for the certain device. If no parameters
were configured, we use the default values.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Introduce hdev->pending_auto_conn list

This patch introduces the hdev->pending_auto_conn list which holds
the device addresses the kernel should autonomously connect. It also
introduces some helper functions to manipulate the list.

The list and helper functions will be used by the next patch which
implements the LE auto connection infrastructure.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Introduce LE auto connection infrastructure

This patch introduces the LE auto connection infrasctructure.
This infrastructre will be used to implement the auto_connect
options from hci_conn_params.

The auto connection mechanism works as follows: When the first
device address is inserted into hdev->pending_auto_con list, we
start the background scanning. Once the target device is found
in range, the kernel creates the connection. If connection is
established successfully, the device address is removed from
hdev->pending_auto_conn list. Finally, when the last device
address is removed, the background scanning is stopped.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bleutooth: Add support for auto connect options

This patch adds support for the HCI_AUTO_CONN_ALWAYS and HCI_AUTO_
CONN_LINK_LOSS options from struct hci_conn_params.

The HCI_AUTO_CONN_ALWAYS option configures the kernel to always re-
establish the connection, no matter the reason the connection was
terminated. This feature is required by some LE profiles such as
HID over GATT, Health Termomether and Blood Pressure. These profiles
require the host autonomously connect to the device as soon as it
enters in connectable mode (start advertising) so the device is able
to delivery a notification or indication.

The BT_AUTO_CONN_LINK_LOSS option configures the kernel to re-
establish the connection in case the connection was terminated due
to a link loss. This feature is required by the majority of LE
profiles such as Proximity, Find Me, Cycling Speed and Cadence and
Time.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Temporarily stop background scanning on discovery

If the user send a mgmt start discovery command while the background
scanning is running, we should temporarily stop it. Once the discovery
finishes, we start the background scanning again.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Auto connection and power on

This patch implements a fixup required by auto connection mechanism
in order to work properly after a power on.

When hdev is closed (e.g. Mgmt power off command, RFKILL or controller
is reset), the ongoing active connections are silently dropped by the
by the controller (no Disconnection Complete Event is sent to host).
For that reason, the devices that require HCI_AUTO_CONN_ALWAYS are not
add to hdev->pending_auto_conn list and they won't re-connect. So to
fix this issue, after adapter is powered on, we should add all HCI_
AUTO_CONN_ALWAYS address to hdev->pending_auto_conn list.

This way, the auto connection mechanism works propely after a power
off and power on sequence as well as RFKILL block/unblock.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Add thread-safe version of helpers

This patch adds the thread-safe version of helper functions to add
and remove pending auto connections. These helpers will be used in
next patches to implementing the Mgmt add/remove connection
parameters commands.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Mgmt command for adding connection parameters

This patch introduces a new Mgmt command (MGMT_OP_ADD_CONN_PARAMS)
to specify the connection parameters the kernel should use when
establishing connections to a certain device. Moreover, this command
also specifies the auto connection option the device requires.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Mgmt command for removing connection parameters

This patch introduces the MGMT_OP_REMOVE_CONN_PARAMS which removes
from hdev's list the connection parameters from a given device.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>